Abstract: A pharmaceutical composition suitable for administration to human beings for suppressing the production of factor VIII inhibitor includes:an immune complex of factor VIII antigen component and factor VIII inhibitor component, the components being present in a ratio such that the inhibitor blocks essentially all relevant binding sites of the antigen; anda pharmacologically acceptable carrier or diluent. The invention also provides a method of administering the compositions to suppress the production of inhibitor to factor VIII.

Abstract: A pharmaceutical composition comprises an immune complex of an allergen and a purified antibody specific thereto, the allergen being selected from a specific subclass of antigen which causes immediate hypersensitivity that is mediated by IgE antibody, and a pharmacologically acceptable carrier or diluent. The method of using the compositions in the treatment of immediate hypersensitivity to the allergen is also described.

Abstract: A biological fluid from a first animal species (e.g. human serum) is assayed for an immunogen therein by mixing with the fluid (Ig-minus-Fc) fragments of an immunoglobulin from a second animal species (e.g. rabbit), the immunoglobulin being immunospecific to the immunogen or another component of the mixture whereby the immunogen can be determined. Interference can occur from reaction between first animal species antibodies and the said fragments, and in the method of the invention this interference is avoided or overcome, preferably by also including in the mixture different (Ig-minus-Fc) immunoglobulin fragments from the second animal species which react with said antibodies but not with said immunogen. These different fragments are preferably aggregated. The method of the invention is particularly applicable to particle agglutination assays.

Abstract: A method for immunological assay of IgM antibodies against at least one said antigen in a liquid sample containing at least IgM and IgG antibodies, such as a biological fluid, comprising reaction of said liquid sample and of antibodies against IgG, and addition to the so obtained reaction product of the said antigen bound to finely divided particles and of a free said antigen, the amount of IgM being inversely proportional to the amount of unagglutinated finely divided particles.

Abstract: A process of immunoassay of a selected substance in a liquid sample containing one or more other non-selected substances, each of these substances being comprised of at least two structurally different chains, the process comprising among others addition of a dissociating agent, such as for example a proteolytic enzyme, to the sample, mixing of the so-obtained liquid, inactivation of the dissociating agent, addition of antiserums, and determination of the amount of this selected substance in the liquid sample.

Abstract: In a particle agglutination assay for an antigen (Ag), there is included in the mixture a limited amount of a substance which binds univalently with a proportion of the Ag present, that Ag which is so bound being unable then to cause agglutination of the particles. In this way, unusually large concentrations of Ag can be assayed in that a proportion of the Ag is bound to the univalent substance and the particle agglutination assay is in effect conducted on the smaller amount of Ag still remaining free in solution.

Abstract: In the immunoassay of a particular protein in a biological fluid, there is frequently interference in the assay by other proteins present in the fluid, e.g. by complement factors or antibodies in human serum. The interference so caused can be avoided by subjecting the fluid to protein-digestion, using for example an enzyme such as pepsin, as a result of which the particular protein of interest, or a fragment thereof, can be assayed without interference by the other proteins. Also, radioallergosorbent tests for particular IgE antibodies can be improved in sensitivity and accuracy, by subjecting the absorbed IgE to enzymic digestion, and then assaying a fragment thereof.

Abstract: A particle counting assay for haptens (small non-protein monovalent substances having a molecular weight below 1500) comprises mixing a liquid sample (e.g. of human origin) containing the hapten, with finely divided inert particles bearing the same hapten (or a specific analogue thereof), an agglutinator such as RF or C1q, and a measured amount of antibody, which amount is insufficient to cause agglutination of all the particles. The amount of hapten is determinable by measuring the extent of the agglutination.

Abstract: Immunoassays for antigens or haptens are effected using, instead of an immunoglobulin antibody, the F(ab').sub.2 fragments thereof. In this way, interference from endogenous RF and Clq in the fluid under assay is avoided without the necessity of pre-treating the fluid to remove or inactivate the RF or Clq. The assays may be of various types including latex agglutination and competitive binding assays. A reagent for such use comprising F(ab').sub.2 fragments insolubilized on a water-insoluble substrate, especially a particulate substrate, is described.

Abstract: In particle agglutination immunoassays for an analyte (e.g. an antigen or antibody) in a liquid sample (e.g. human serum), interferences arise due to non-specific protein-protein interactions and the like. These interferences are reduced or overcome by including in the assay mixture a chaotropic or chaotropic-like agent, in a carefully controlled amount. Such agents include guanidine, guanidinium hydrochloride or thiocyanate, sodium or ammonium thiocyanate, and urea, sodium chloride and ethylenediamine tetraacetic acid.

Abstract: A liquid, particularly but not exclusively a liquid of human origin such as blood serum or urine, is immunoassayed for antibodies, antigens or antibody: antigen complexes, using as a reagent in the analysis an active fraction from mouse ascitic fluid. This active fraction is a euglobulin and has the ability, like human C1q, to combine with antibody:antigen complexes but not with free antibody or antigen. Unlike human C1q, however, it remains active at high pH's and its activity is not destroyed by 0.1 M putrescine or 0.1 M hydrazine, so analyses on human body fluids can be carried out at high pH's or in the presence of putrescine and hydrazine, without interference from endogenous human C1q. The active fraction is a very broadly applicable reagent in immunoassays and particularly useful in techniques involving agglutination of latex particles.

Abstract: Biological fluids, such as serum, are analyzed for the presence, nature and/or amount of antibodies, antigens and antibody:antigen complexes therein using as a reagent, insolubilized rheumatoid factor or insolubilized Clq. These reagents are themselves novel. They bind to antibody:antigen complexes, but not to free antibodies or antigens, and complexes can thus be removed from mixtures thereof with other materials, such as antibodies and antigens.

Abstract: A particle agglutination assay for antigens, antibodies and other binding proteins such as rheumatoid factor, uses two different, microscopic or submicroscopic particulate reagents. The first particulate reagent binds with the antigen or antibody under assay, and then the second particulate reagent is added which binds only to those first reagent particles which have bound to the antigen or antibody under assay, so causing agglutination. The free unbound first or second particles are assayed to indicate the presence and/or amount of the antigen or antibody under assay. The assay of rheumatoid factor may be so conducted to reveal the fractions of each immunoglobulin class of RF present. The assay is particularly useful for small quantities of antibodies present in human sera indicating allergy, infection or autoimmune diseases.

Abstract: Insolublized antibodies, F(ab').sub.2 fragments thereof and protein antigens are made by coupling to a water-insoluble substrate using a bridging agent which covalently binds to sulphur atoms in antibody, fragment or protein rather than to free amino groups therein. This is preferably effected by using a chloracetyl-terminated bridging agent. Immunoassays utilizing these insolubilized reagents are described. One novel class of bridging agents comprising anhydride and monochloracetyl end groups, which is useful for making the said reagents, is also disclosed.

Abstract: The presence of antibodies (Ab) and antigens (Ag) in a liquid is detected by mixing the liquid with two different particulate reagents which mutually agglutinate but whose agglutination is inhibited by the particular Ab or Ag under assay. By detecting the extent of agglutination, the presence or absence of the Ab or Ag can be confirmed. By measuring the extent of agglutination or non-agglutination quantitatively, an amount of Ab or Ag can be determined. The particulate reagents preferably comprise latex.

Abstract: In the analysis of liquids, particularly biological liquids such as serum or urine, mouse serum or a component of mouse serum is used as a reagent. The reagent has the ability to combine with antibody:antigen complexes (but not free antibody or antigen) and to combine with IgG and IgM. It differs markedly from human C1q in that it remains active at high pH and in the presence of certain substances known to destroy human C1q. It is a very broadly applicable reagent in immunoassays, and particularly useful in techniques involving agglutination latex particles.

Abstract: Biological fluids, such as serum, are analyzed for the presence, nature and/or amount of antibodies, antigens and antibody:antigen complexes therein using as a reagent, insolubilized rheumatoid factor or insolubilized C1q. These reagents are themselves novel. They bind to antibody: antigen complexes, but not to free antibodies or antigens, and complexes can thus be removed from mixtures thereof with other materials, such as antibodies and antigens.

Abstract: A method of determining Ab:Ag complex in a biological fluid sample comprising adding to the sample a solution of RF or Clq and a known quantity of a material, such as immunoglobulin-coated polystyrene particles, which is caused to agglutinate on contact with RF or Clq, and detecting the amount of material which is not agglutinated.